Display screen or portion thereof with a graphical user interface



FIG. 1 is a front view of a display screen or portion thereof with agraphical user interface showing a first embodiment of the new design;

FIG. 2 is another view of the claimed design as shown in FIG. 1 , butwith different broken line subject matter; and,

FIG. 3 is a front view of a second embodiment of the claimed design.

The outermost broken line rectangle illustrates a display screen orportion thereof and forms no part of the claimed design. The remainingbroken lines illustrate portions of the graphical user interface thatform no part of the claimed design.

CLAIM I claim the ornamental design for a display screen or portionthereof with a graphical user interface, as shown and described.